Stem leaf diagram marks test for group of students
5
6
7
8
4 6 7 7 7 9
2 3 4
0 2 3 4 6
2 3 4 5 7 9
key; 5|4 = 54%
(a) the mark for the top student has been left out
range for complete class of 20 students  was   35
calculate the mark for the top student, insert into table
range = 35 + 54 = 89
 or      =  89 - 35 = 54
(b)what was the mean for the lowest 4 marks?
54 + 56 + 57+ 57  = 224 ÷ 4 = 56
or (4 + 6 + 7 + 7 )÷ 4 = 6
(c) top 15% of all students in the class awarded A* grade
what was the lowest mark in A* grade?
             15% of 20 students =  15     100
                                                                                      ---    X -----    = 75%  = 3 students
                                                  20        1

8 |2 3 4 5 7 9                      score  at least 85%